Nowadays, woody moldings are used in residential buildings as interior components, for example, rims, skirting bases, stair handrails, stair footboards, sash frames and pieces of furniture like tables and counters.
For production of such woody moldings, at first, cellulose based fine powdery particles are obtained from, for example, crushed natural wood and sawdust. Then, the cellulose based fine powdery particles are kneaded and dissolved with resin, and this composite material is extruded into pellets as a temporary shape. Finally, these pellets are used in extrusion molding or injection molding to produce appropriate shapes for such woody moldings.
As a method for producing such pellets, here, reference is made to a technique disclosed in Japanese Laid-Open Patent Publication No. H8-183028, which describes an injection-molded part of a synthetic resin as an interior part for use in automobile cabins.
At first, appropriate quantities of a thermoplastic resin such as polypropylene resin or ABS resin and a reinforcing filler such as talc or calcium carbonate are put into a Henschel mixer and mixed there. Then, the mixed material which has completed a mixing step by the Henschel mixer is supplied to an extruder and further mixed and kneaded there with additions of the thermoplastic resin and the reinforcing filler and then extruded through a die into a bar of resinous material. This bar of resinous material extruded through a die from the extruder is passed through a protein-powder adhesion machine, which provides protein powder that sticks the outer surface of the resinous material. Subsequently, the resinous material is cooled to a predetermined temperature in a coolant tank, and it is then made into resin pellets with an appropriate particle size by a pelletizer.
In other words, in the method disclosed in Japanese Laid-Open Patent Publication No. H8-183028, after the mixing step, the mixed material is made into the bar of resinous material through an extruder, cooled in a coolant tank, and then cut into resin pellets with an appropriate particle size by the pelletizer, and these pellets are used to produce injection-molded articles by injection molders.
Therefore, the production of molded articles in this method involves a relatively large number of processing steps. As a result, the processing is complicated, and it is difficult to reduce the total processing time.
The present invention has been developed in light of the above circumstance, and it is an object of the present invention to provide a method and an apparatus for producing woody moldings which can reduce the number of processing steps and shorten the processing time.